A False Sense of Privacy: Towards a Reliable Evaluation Methodology for the Anonymization of Biometric Data

Biometric data contains distinctive human traits such as facial features or gait patterns. The use of biometric data permits an individuation so exact that the data is utilized effectively in identification and authentication systems. But for this same reason, privacy protections become indispensably necessary. Privacy protection is extensively afforded by the technique of anonymization. Anonymization techniques protect sensitive personal data from biometrics by obfuscating or removing information that allows linking records to the generating individuals, to achieve high levels of anonymity. However, our understanding and possibility to develop effective anonymization relies, in equal parts, on the effectiveness of the methods employed to evaluate anonymization performance. In this paper, we assess the state-of-the-art methods used to evaluate the performance of anonymization techniques for facial images and for gait patterns. We demonstrate that the state-of-the-art evaluation methods have serious and frequent shortcomings. In particular, we find that the underlying assumptions of the state-of-the-art are quite unwarranted. State-of-the-art methods generally assume a difficult recognition scenario and thus a weak adversary. However, that assumption causes state-of-the-art evaluations to grossly overestimate the performance of the anonymization. Therefore, we propose a strong adversary which is aware of the anonymization in place. This adversary model implements an appropriate measure of anonymization performance. We improve the selection process for the evaluation dataset, and we reduce the numbers of identities contained in the dataset while ensuring that these identities remain easily distinguishable from one another. Our novel evaluation methodology surpasses the state-of-the-art because we measure worst-case performance and so deliver a highly reliable evaluation of biometric anonymization techniques

Corticomuscular synchronization with small and large dynamic force output

BACKGROUND: Over the last years much research has been devoted to investigating the synchronization between cortical motor and muscular activity as measured by EEG/MEG-EMG coherence. The main focus so far has been on corticomuscular coherence (CMC) during static force condition, for which coherence in beta-range has been described. In contrast, we showed in a recent study [1] that dynamic force condition is accompanied by gamma-range CMC. The modulation of the CMC by various dynamic force amplitudes, however, remained uninvestigated. The present study addresses this question. We examined eight healthy human subjects. EEG and surface EMG were recorded simultaneously. The visuomotor task consisted in isometric compensation for 3 forces (static, small and large dynamic) generated by a manipulandum. The CMC, the cortical EEG spectral power (SP), the EMG SP and the errors in motor performance (as the difference between target and exerted force) were analyzed. RESULTS: For the static force condition we found the well-documented, significant beta-range CMC (15-30Hz) over the contralateral sensorimotor cortex. Gamma-band CMC (30-45Hz) occurred in both small and large dynamic force conditions without any significant difference between both conditions. Although in some subjects beta-range CMC was observed during both dynamic force conditions no significant difference between conditions could be detected. With respect to the motor performance, the lowest errors were obtained in the static force condition and the highest ones in the dynamic condition with large amplitude. However, when we normalized the magnitude of the errors to the amplitude of the applied force (relative errors) no significant difference between both dynamic conditions was observed. CONCLUSIONS: These findings confirm that during dynamic force output the corticomuscular network oscillates at gamma frequencies. Moreover, we show that amplitude modulation of dynamic force has no effect on the gamma CMC in the low force range investigated. We suggest that gamma CMC is rather associated with the internal state of the sensorimotor system as supported by the unchanged relative error between both dynamic conditions

Fluids in the treatment of diabetic ketoacidosis in children:A systematic review

Aim: To determine the comparative effectiveness of fluid schemes for children with diabetic ketoacidosis (DKA). Methods: We conducted a systematic review with an attempt to conduct network meta-analysis (NMA). We searched MEDLINE, EMBASE, CENTRAL, Epistemonikos, Virtual Health Library, and gray literature from inception to July 31, 2022. We included randomized controlled trials (RCTs) in children with DKA evaluating any intravenous fluid schemes. We planned to conduct NMA to compare all fluid schemes if heterogeneity was deemed acceptable. Results: Twelve RCTs were included. Studies were heterogeneous in the population (patients and DKA episodes), interventions with different fluids (saline, Ringer's lactate (RL), and polyelectrolyte solution-PlasmaLyte®), tonicity, volume, and administration systems. We identified 47 outcomes that measured clinical manifestations and metabolic control, including single and composite outcomes and substantial heterogeneity preventing statistical combination. No evidence was found of differences in neurological deterioration (main outcome), but differences were found among interventions in some comparisons to normalize acid-base status (∼2 h less with low vs. high volume); time to receive subcutaneous insulin (∼1 h less with low vs. high fluid rate); length of stay (∼6 h less with RL vs. saline); and resolution of the DKA (∼3 h less with two-bag vs. one-bag scheme). However, available evidence is scarce and poor. Conclusions: There is not enough evidence to determine the best fluid therapy in terms of fluid type, tonicity, volume, or administration time for DKA treatment. There is an urgent need for more RCTs, and the development of a core outcome set on DKA in children.</p